Vodacom is a bunch of ******!

I have just received my invoice and statement. Usually my invoice for my ****le is around R450 max. When I signed up for this contract a few years ago (I think in 2009/2010) I signed up for a Top Up. All 3 my contracts with Vodacom are Top Ups. This month I received my invoice to a MAJOR shock of almost R1555! With a letter saying something about a moving to a new system hence why I have two invoices. The Call Centre lady (Cindy) wasn't really helpful as she had to keep on going between the new system and the old system. I asked to speak to a manager and she put me through to Kuda, the team leader. Both these people couldn't really give a positive answer. They just kept on saying that I went over my 2GB and was then charged out of bundle rates. How can this be when I am suppose to be on a Top Up? Well, I can tell you. According to Kuda, when I last upgraded I did not upgrade to a Top Up but something else. Now please tell me, why would I move from something I have always used to something new and expensive? Could someone please send me a detailed itemised bill for my number in question so that I can see since when this \out of bundle rates\" started?"